So, It seems I've only noticed this on Comcast HD channel thus far... first on John Adams... and I assumed it was just a DVR thing.. but now I'm noticing it on all the other channels of HD.

There's just this... line that kinda rolls from the bottom to the top of the screen. Its transparent, and hard to notice, but it's there. And it's damn annoying.

Anyone else experience this?

<- Samsung 61" DLP --

Sounds like a ground loop problem to me. Do a search for ground loop in the display or HDTV hardware reception forums. If you have cable TV, odds are that the co-axial cable line is not properly grounded.